Expose persistent serial numbers for local disks

A guest querying the hardware properties of a disk will currently see a serial number for a volume, but not for a local disk (local root, ephemeral, or swap). This feature will add a persistent serial number for local disks.

Work Items

Work items:
Add a DriverBlockDevice class for local disks from image: TODO
Add 'root' to block_device_info: TODO
Add 'serial' to all DriverBlockDevice classes: TODO
Expose serial for local disks in libvirt driver: TODO